1. Field of the Invention
The invention relates to a bumper bracket for a motor vehicle body, comprising a first profiled section having a three-dimensional structure and a second component that spatially closes the first profiled section.
2. Description of the Prior Art
Bumper brackets of the type in question are used in a motor vehicle body. Essential aspects for the bumper bracket according to the invention are for the bumper bracket to offer effective protection for the interior space of the motor vehicle body relative to the direction of an anticipated impact, which is essentially transverse to the longitudinal extension of the bumper bracket, and to allow connection to the associated structural component of the motor vehicle body.
In the spirit of lightweight construction in modern vehicle manufacturing, the bumper bracket not only absorbs the energy during use in the event of a crash, but also contributes to reinforcing the structure during the vehicle's operation. For this purpose, the bumper bracket is connected to the longitudinal beams of the vehicle structure in a flexurally and torsionally rigid manner. The geometry of the bracket is determined by rigidity requirements and by a high-energy absorption capacity at the lowest possible weight and acceptable manufacturing costs. The requirements in regard to the energy absorption capacity are determined by insurance, statutory and manufacturer-specific regulations.
It is already known to use a hollow profiled section made of steel or aluminum as a bumper bracket for a motor vehicle body, wherein starting from a pipe, the hollow profiled section is designed as a single-piece profiled steel section having high strength, robustness and deformation work, the end regions of the section being designed in a tab-like manner for attachment to the structural component, in particular in the motor vehicle door (DE 41 33 144 A1). The pipe can have a round, or oval, or also an elliptical cross-section. It is also possible for two pipes to be disposed next to each other relative to the direction of an anticipated impact. A bumper bracket for a motor vehicle body, comprising two profiled pipe sections disposed next to each other relative to the direction of any anticipated impact, has already been further developed from a manufacturing point of view such that both profiled pipe sections are integrally formed of steel strip that has been brought into the target cross-sectional form by way of a roll forming method, wherein the steel strip forming the profiled pipe sections is fixed at the connecting points by a longitudinal seam weld joint (U.S. Pat. No. 6,591,577 B2).
One known type of bumper bracket is shown in U.S. Pat. No. 7,926,865, which teaches a bumper bracket that has a mounting plate in a band-like shape and a hat-shaped mounting element. The two components of the bumper bracket are joined by upper and lower joint flanges and connected to the crash boxes. The type of the joint is not described in detail.
It is also known not to produce the profiled sections as closed pipes, but form them from sheet steel in the manner of a hat. Structures having a double hat form are also possible. The profiled sections are closed with a cover so as to create greater stability and rigidity.